Quinidine

Definition

An alkaloid extracted from the bark of the Cinchona tree with class 1A antiarrhythmic and antimalarial effects. Quinidine stabilizes the neuronal membrane by binding to and inhibiting voltage-gated sodium channels, thereby inhibiting the sodium influx required for the initiation and conduction of impulses resulting in an increase of the threshold for excitation and decreased depolarization during phase 0 of the action potential. In addition, the effective refractory period (ERP), action potential duration (APD), and ERP/APD ratios are increased, resulting in decreased conduction velocity of nerve impulses. Quinidine exerts its antimalarial activity by acting primarily as an intra-erythrocytic schizonticide through association with the heme polymer (hemazoin) in the acidic food vacuole of the parasite thereby preventing further polymerization by heme polymerase enzyme. This results in accumulation of toxic heme and death of the parasite.

Also known as QUINIDINE — per NCIT

Also identified as

• ATC C01BA01 per RXNORM
• NCIT NCIT:C793 per NCIT
• SCTID 31306009 per RXNORM
• SCTID 372697008 per RXNORM
• UNII ITX08688JL per RXNORM

Indications

Organ Effects

1 entry above is marked DERIVED: Atlas Médico inferred it by combining two sourced claims, and no source asserts this link directly. Treat it as a navigation aid, not as a clinical statement.